For Norway the reason is fish. Since they're not in the EU, they don't have to allow others access to fish in their waters.
It's still largely politically untenable in Norway to oppose agriculture subsidies.
Today the main reminder is that Norwegian school children still tend to learn the epic poem "Terje Vigen" by Ibsen, about a man who braves the blockade to feed his family and is captured - coupled with food security being a talking point in other subjects. It's not pushed very hard, and many probably at this point don't even make the connection.
The main modern justification is WW2, where the subject of food security gets reinforced with stories of bread made with bark etc., and post-war rationing.
Couple that with the constant fear of the Soviet Union (to the point that when growing up, we had regular air raid siren tests - today they're so rare the newspapers write articles to explain what they are) only reducing to unease about Russia, and food security is still a political topic.
Personally I don't mind the sirens, they tend to work pretty reliably and every time the mobile phone network was used to indicate something was up for some reason I totally missed the message, never received it or received it more than a day later.
EDIT: That's not to say Norway doesn't still do whaling, but quotas are only for minke whales. Of a quota of 1278 for 2019, 429 where caught. But pilot whales explicitly still do not meet the conditions required (size of population etc.) for Norway to allow hunt.